Methods and apparatus which utilize ultrasound energy for diagnostic imaging of targeted anatomical organs and blood flow are known. Typically, ultrasound energy is directed into and scattered from body tissues. The amplitude envelope of the scattered ultrasound energy known as an echo is detected and displayed to form an image which characterizes the targeted structures.
Virtually all commercial medical ultrasound imaging systems form images from the amplitude envelope of the scattered ultrasound energy that is returned by an interface of different organ tissue types having different acoustic impedances. Although the prior art systems attempt to delineate various body organs, they cannot identify different types of organ tissue or identify various structures within the same tissue. Further, these systems fail to make use of the phase information of the scattered ultrasound energy which is particularly useful to image and identify tissues and their various constituent structures.